Oligosaccharides from breast milk could protect against GBS

Sugars in human breast milk are known for their immunogenic properties. A new study has investigated this further, demonstrating that these oligosaccharides may have antimicrobial and anti-biofilm properties against Group B Streptococcus (GBS).

GBS remains a leading cause of sepsis and meningitis in new-borns, as lead author, Steven Townsend (Vanderbilt University, TN, USA), explained: “In most women, the GBS that is present will not cause illness. But for newborn babies, a GBS infection often leads to sepsis or pneumonia, and in severe cases death, because they don’t have fully developed defense mechanisms.”

It has previously been proposed that breastfeeding could represent one mode of transmission, and that this may increase the risk for late-onset sepsis. This study, presented at the 254th National Meeting & Exposition of the American Chemical Society (20–24 August, Washington DC, USA), looked to investigate why some infants become infected by breastmilk, whereas others do not.

Townsend commented: “As carbohydrate chemists, we knew from previous research that milk carbohydrates are protective against other bacteria, so we figured there would be a chance they would be active against GBS too.”

The team initially assessed five breast milk samples from donors, isolating the oligosaccharides and growing GBS in their presence. They discovered that some mothers produce protective sugars that may help prevent infection.

Townsend expanded: “In the initial study, the sugars from one mother’s milk killed nearly the entire colony. Another milk sample was moderately effective, while the remaining three showed diminished activity.”

Building on these results, the team is testing additional samples. To date, two samples have demonstrated activity against bacteria and biofilms, two had activity against bacteria only, four against biofilms only and six were relatively ineffective against both.

Preliminary data from the researchers has also suggested that some breast milk oligosaccharides may affect bacterial susceptibility to common antibiotics, such as penicillin and erythromycin.

Oligosaccharides are known for their immunogenic properties; however, these findings demonstrate that the sugars may also act as antimicrobial and anti-biofilm agents. The study is the first to report carbohydrates functioning as anti-biofilm agents.

Further studies will look to investigate the effects of individual sugars on GBS and hope to identify the structural motifs responsible for antimicrobial and anti-biofilm properties. If results bear out, sugars could become part of treatment for infants suffering from GBS, reducing dependence on common antibiotics.

Townsend concluded: “The great thing about these sugars is that if they’re safe for babies, they should be safe for everyone.”